I'm thinking about installing one of those pilot-less propanewater heaters that makes instant hot water, and I'd be interested in hearing the pros and cons of these devices by people that have them. Do they make enough hot water on demand to replace a conventional marine water heater?

sounds like a bomb waiting to happen,unless it can be installed outside,propane water heaters were not designed for marine applications,better off fitting an eberspacher diesle water heater and calorifier with a twin loop using the enginecooling as well.

I have used them and didn't like it! It leads to waste of water. They work fine after adjustment, if you shower like one does in a house. However, on a boat you get wet, soap up with the water off, and rinse. Same with washing your hair. These units lead to being too cold, then too hot, then after adjustment... just right. There is a lot of water waste getting to just right, EACH TIME you turn it back on!

We use a 2.5 gallon black plastic garden sprayer, with dish washing nozzel. We set it in the sun 2 hours before sunset, and it reaches a "perfect" temperature. Then we shower while sitting on a boat cushion in the cockpit footwell. It is just enough for two, (Inc. hair), minimizes water waste, and reduces moisture down below that leads to damp air and more mildew growth.

I have seen them on some boats and have used the equivalent electric shower unit. If the unit is very close to the end use it is not too bad, however if you mount the heater a ways away from your shower you will be wasting a lot of water. Or enjoying cold and hot showers at the same time. lol

I installed a Paloma unit on my 41' ketch. It came with disclaimers about not using it on boats, and warnings from so many dock experts about the dangers of open flames inside my cabin!! (the majority of who cooked with propane stoves.)

We loved it, and never had a single regret. We kept the gas OFF unless we were making hot water, which is the same practice most every sailor uses for propane cooking. If you already have propane cooking on board, I can't see how a water heater makes things more dangerous than they already are.

Agree with Doug. I have a propane heater. I've vented it through the deck, and have monoxide and propane detectors near the unit. My unit has no pilot light, and detects a failure to light or flame out and turns the gas off.

I haven't had an issue with the unit cycling and the water getting hot then cold. I set the unit's temperature slightly above what I want, then adjust at the faucet.

One potential issue is that a propane cylinder has a maximum rate at which it can supply propane gas. In a cold climate, with a near empty 20lb tank, a single tank will not supply enough gas to heat water to hot. The solution would be paralleling another 20lb tank if you have the room in your locker.

I was very happy with the Wolter unit I had; shame they aren't made anymore.
If you don't have an inboard engine, they are a good solution. Now with an inboard and "normal" water heater, sometimes (when under sail for long periods) it would be nice to have the propane unit, but not nice enough to have both.

Thanks for the feed back guys, and this is what lead me to ask about these propane water heaters.

On our boat we had a Seaward 5 or 6 gallon water heater located under a salon floor board, behind the engine on a shelf over the transmission. I had some work done on our boat, and part of the work was replacing the old PSS with a new one. The shelf the water heater was on made access to the PSS almost impossible, so I took the water heater and shelf out for good access. Now that the shelf is out I really hate to lose the access to the PSS, so I've been thinking about relocating the water heater.

There is no other place I can put a new conventional water heater other than in a cockpit lazarette (which I don't want to do), and keep the water heater lower than the engine coolant reservoir tank. The one place I wanted to put it under the large, raised quarter berth would place the top of the water heater at least two feet above the engine, and I'd have to install another reservoir slightly higher than the water heater. Then use a higher pressure cap on the present lower reservoir, and a lower pressure cap on the higher reservoir. The problem with this is, I can't think of a good location that high for a reservoir that I can access easily. So that make me think about another option, and that's why I asked about a pilot-less propane water heater.

I've heard about insurance concerns before, so that is the one major thing that's holding me up more than anything else. I'm going to communicate with our insurance company, and see if they maybe have approved models of propane water heaters they will insure for.

I had one at my last house (now a rental) and it never ran out of hot water. If you can get one the size you want, go pilotless, it'll save the open flame syndrome, and works great, 7 years now. They have a little paddle wheel driven generator that lights on water flow. Bosch is the brand we have.

I installed a PrecisionTemp ShowerMate propane marine water heater - it is stainless an specifically designed for boats - so not cheap. I have used it on two boats and it works great - we are year round live aboards in New England. When we got PEREGRINA, the 20 gallon water heater was disconnected - there had been airlock problems because it was mounted above the engine. The propane heater is mounted in the same place a cabinet behind the shower. It has a fan forced exhaust venting through the cabin side -2 inch exhaust line - I think. Nice to have a shower anytime without starring the engine or need to be at the dock!

If you read the ABYC guidelines for propane appliances, you will find that a water heater needs to have a sealed combustion chamber and both draw combustion air from, and exhaust to the exterior of the boat. If you can find such a heater then you can probably convince yourself and others that it meets guidelines, assuming you care.

This came up elsewhere in the context of propane fridges, in which case I'm not aware of any that offer the sealed combustion, outside air/exhaust capability. With a water heater, you might be able to pull it off.

I have used them and didn't like it! It leads to waste of water. They work fine after adjustment, if you shower like one does in a house. However, on a boat you get wet, soap up with the water off, and rinse. Same with washing your hair. These units lead to being too cold, then too hot, then after adjustment... just right. There is a lot of water waste getting to just right, EACH TIME you turn it back on!

We use a 2.5 gallon black plastic garden sprayer, with dish washing nozzel. We set it in the sun 2 hours before sunset, and it reaches a "perfect" temperature. Then we shower while sitting on a boat cushion in the cockpit footwell. It is just enough for two, (Inc. hair), minimizes water waste, and reduces moisture down below that leads to damp air and more mildew growth.

IF the simple solution solves the problem, it is the best solution!

Mark

Correct; you can't turn the wate on and off. Set it and leave it. It helps if the point of use is close to the heater; the tuning waste is less. If people use shore-side habits, very few boats will have the tankage to shower a family!

As for Sun Showers, had one. Generally, if it was hot enough to work it was warm enough I just showered cold.